JPS5910434A - Thread working method by rolling - Google Patents

Abstract

PURPOSE:To work thoroughly screw threads just before a step part by mounting circular dies with the chamfer and flank positioned reverse from an ordinary case, inserting loosely the work which has the step part and with which through- rolling is infeasible into the space between the dies just before the step part before working thereof, subjecting the work to rolling and allowing the work to walk backward. CONSTITUTION:Each die 1 is disposed in order of a flank 4, a forming part 3 and a chamfer 2, reverse from an ordinary case. Thereupon, the part to be worked with screw threads of a work piece P which has a step part P1 and with which through-rolling is infeasible is inserted freely into the space between the dies 1 just before the part P1. The safe distance S between the end face of the part P1 and the end face of the dies 1 can be made much smaller than the distance in the prior art. If the work piece P is subjected to prescribed rolling in this stage, the work piece is walking-rolled in the direction reverse from the insertion direction and is returned out backward, whereby the rolling is completed. The length E' of the imperfect thread part is thus decreased considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thread processing method using a rolling machine, and is a thread processing method that can form a complete thread to just before the step in a workpiece that has a step or the like and cannot be rolled through. Regarding the method.

Today, most screws are manufactured by rolling, and the rolling process of screws makes it easy to achieve the highest precision of currently used threaded parts, and increases static strength and fatigue strength compared to cutting screws. It has excellent features. In addition, since the thread is formed at the same time as the bolt head is forged, productivity is high, and no processing waste is produced, making it economical.

On the other hand, in the case of workpieces that have stepped parts and cannot be subjected to through rolling or synchronous forming as described above, for example, parts such as the foot of a switch with a long threaded part may be processed by so-called walk rolling. The desired threaded portion is formed by activating a limiter at a predetermined position in front of the stepped portion.

However, dies for round die rolling machines that perform this walk rolling generally have a taper part of a chamfer and a relief part on the inlet and outlet sides to make it easier to insert the material and to prevent sudden changes in pressure. Smooth molding is considered.

That is, as shown in Fig. 1 and Fig. b, the die (1) is
The body is composed of a chamfering part (2) on the entry side, a relief part (4) on the exiting side, and a forming part (3), and the workpiece (P) that has been inserted from the chamfering part (2) is Molded and diced (1)
Walking and turning is stopped after a predetermined safe distance M (S) between the end face on the person side and the end face of the stepped portion (Pl) of the workpiece (P). Accordingly, in the workpiece (P), the food FJ part (
2) The length L) corresponds to the complete thread length, and the length E) equivalent to the above safety distance (S) is the incomplete thread length.

By the way, a member such as the above-mentioned front rod consists of a threaded part and a flat plate part, and the threaded part is directly connected to the stepped flat plate part.
) [It is desirable that the thread be fully threaded up to 1".-t"
In this case, in order to shorten the length of the chamfering part (2) of the die (1), it is possible to increase the chamfering angle (α) of the chamfering part (2), but this would cause severe damage to the die. This causes problems such as the need to replace expensive dice sooner.

This invention proposes a method for threading a member having a stepped portion, such as a front rod, by molding a complete threaded portion up to just before the stepped portion.

That is, in the method of thread rolling by walk rolling using a round die turning machine, the chamfered part and relief part positions of the round die are installed in the opposite direction to the normal direction, and the round die has a stepped part and is capable of thread rolling. For workpieces that can be processed with a small
This is a thread processing method by rolling, in which the thread is loosely inserted up to just before the two-phase stepped portion, then rolled, and then returned from between the dies to perform thread processing. It should be noted that the method of the present invention can be applied to all through-rolling, one-step rolling machines.

The present invention will be explained in detail below based on the drawings.

FIG. 2A is a perspective view of a die and a workpiece showing the rolling method (hereinafter referred to as back rolling) according to the present invention, and FIG. 2B is an explanatory diagram of the die.

Generally, when rolling long screws with a two-round die rolling machine, the above-mentioned walk rolling, in which the workpiece is fed in the axial direction, is
However, there are two ways to do this. One of them is
This is a method in which one of the two walking turning dies is pushed in to give an effective diameter ΔDr larger than the effective diameter (Dp) of the turning die, and the workpiece is made to walk by the difference in the U-do angle of the die. The method is to perform rolling by tilting both die shafts by the difference IA-Bl between the lead angle (A) of the product screw and the lead angle (B) of the die screw.

Although any of the above-mentioned methods can be applied to the walking turn according to the present invention, the latter method VCm will be explained here.

Trenchless die (1) (1) is a rolling head (not shown)
The die (1) is placed in the opposite direction to the normal direction (7). That is, the die (1) is placed in the order of the relief part (4), the molding part (3), and the double-biting part (2). Arrange so that the chamfered part (2) is at +1 t- on the normal exit side. Therefore, the #i@ angle of IA-Bl connected to the die shaft is normal when viewed from the entry side of the rolling machine. In other words, if normal is positive, it should be set in the negative direction (τ).

In addition, the rolling head here has one die shaft that is fixed, and the other die shaft that is hydraulically operated.
[Be sure to widen the distance between the two dies and place the workpiece (P
) - Loosely insert the U threaded part. At this time, the crotch (Pl
) The safety distance (S) between the end face and the @ face of the die (1) may be much smaller than the conventional distance mentioned above.

As shown in F below, after preparing the rolling head and inserting the workpiece, when the prescribed rolling is performed, the workpiece (P)
is rotated and rotated in the opposite direction to the insertion direction, and then taken out.
Complete thread rolling.

Therefore, when rolling back, the safety distance (S') between the end face of the stepped part (Pl) of the workpiece (P) and the end face of the relief part (4) of the die (1) and the length of the relief part (4) G) The length corresponding to the distance 4 (E') obtained by adding the distance 4 (E') becomes the incomplete thread part of the workpiece (P), and the other parts have a complete thread length up to the tip.

By the way, normally, the relief part (4) length G) of the die is much shorter than the chamfer part (2) length L), and the safety distance (S') is also short as mentioned above, so the workpiece (P
The incomplete thread length E') at ) becomes significantly smaller. That is, when the screw is turned by stepping back and turning, even if there is a step near the top of the thread, a complete thread can be formed up to just before the step, compared to the conventional method.

In addition, walk-back rolling does not require the workpiece to be stopped in front of the stepped portion as in the conventional method, so it is superior in safety during milling.

An example of walk-back rolling will be shown below to clarify its effects.

The workpiece has a total length of 585mm, a screw outer diameter of 88I1ml, and 8
Using the front rod of a 9-way switch, conventional point rolling (test A I,
4) and returning to the steps of the present invention (test boiling 8. A6
) was carried out. - In addition, as a comparative example (test pass 2° A5), a special die with a sharper angle of bite than the conventional walk-turning die was also used. The conditions for implementation were as shown in Table 1.

In addition, the safe distance from the end face of the die is a minimum of 5 WII in the conventional method, and is 5 WII or more in the case of company production, but the minimum value is indicated here.

Table 1 Note: Dimensions of each tie are a 200 mtnφX80m
M1 length (page 7) As is clear from the results in Table 1, when the present invention's back-rolling was performed, the incomplete thread length (K) was significantly shorter than that of the conventional step-back rolling. I understand that. Also,
When the special dies of Tests A2 and Ai5 were used, the incomplete thread length (E) could not be shortened due to the point return transition, and the life was shortened due to the negative (-1 part) damage.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing conventional walk rolling, in which Figure A is a perspective view of a die and a workpiece, and Figure B is an explanatory diagram showing the positional relationship with the die. FIG. 2 is an explanatory diagram showing the rolling method of the present invention,
Figure a is a perspective view of the workpiece and the die, and figure b is an explanatory diagram showing the positional relationship between the workpiece and the die. In the figure, l: die, 2: chamfering part, 8: molding part, 4: relief part, P: workpiece, Pl...
・Danbe. Applicant: Chunichi Seisakusho Co., Ltd. (Page 8)

Claims (1)

[Claims] 1. In the method of thread processing by multi-color rolling using a round die rolling machine, the round die is layered with the chamfered part and relief part positioned in the opposite direction to the normal direction, and has a stepped part so that through rolling is not possible. A method of rolling that is characterized in that before processing, the workpiece material is loosely inserted between the dies in a groove just before the stepped part of the workpiece material, and then the workpiece material is rolled and then walked back from between the dies to perform thread processing. Thread processing method.